Chroma
For the Fokker block concept of chroma, see Fokker block.
The chroma (precisely the moschroma) of a mos scale is the interval that is the difference between the large step and the small step in the scale. The term was suggested as a way to generalize the concept of a sharp or flat (# or b). In particular, the chroma or chromatic semitone in the diatonic scale is the augmented unison, for example, the interval of C-C#.
Moving one note in a mos scale by a chroma leads to a modmos scale if the result is not just a transposition of the original mos scale.